John Ternus officially succeeded Tim Cook as the chief executive officer of Apple on Tuesday, ending Cook's 15-year tenure. ^[1] John Ternus became Apple's CEO on 2026-09-01, succeeding Tim Cook, who had led the company since August 2011. ^[2] Under Tim Cook's leadership from August 2011 to September 2026, Apple's market value grew from about US$350 billion to nearly US$5 trillion, and its stock rose more than 2,000%. ^[3] Apple is expected to unveil its latest iPhone and a new foldable device on September 9. ^[4] John Ternus joined Apple's product design team in 2001 and was appointed senior vice president for hardware engineering in 2021. ^[5] Tim Cook will move into the role of executive chairman following the transition announced in April. ^[6] Apple's annual sales quadrupled to US$416 billion and its weight in the S&P 500 doubled from about 3% to nearly 7% during Tim Cook's tenure. ^[7] Apple's services business, including App Store, iCloud, Apple Music, and Apple Pay, reached 1.5 billion paid subscribers from a base of 2.5 billion active devices under Tim Cook. ^[8]